Self-guiding trailer dolly



Feb. 28, 1950 F. L. WINCHESTER 2,498,779

SELF-GUIDING TRAILER DOLLY Filed March 7, 1947 2 Sheets-Sheet l I l 5o/gu v es G2 f@ G4 eo .2Q 54 A., Il: ;l v 52 94 l v o i I4 l w lo e Il Y58 ,f 9o 40 54 e y' o O o 78 76 8o GG 22 Feb. 28, 1950 F. 1 WlNcHEsTERSELF-GUIDING TRAILER DoLL'Y 2 Sheets-Sheet 2 Filed March 7, 1947Patented Feb. 28, 1950 U N I T ED S TAT-ES PAT EN T O F F 2,498,779 I vSELF-GDNG DOLLY Franklin L. Winchester, South Gate, Calif. ApplicationMarch 7, 1947, Serial No. 733,*'137 512 Claims. o 1

My invention relates toa wheeled 'Support vor dolly particularly-adapted to 'carry the 'front end of trailers and the like.

A particular' advantage O the 'Uresl'lt COnSt'C- tion is an arrangementor parts vkwliereloy `the wheels 'and undercarr'a'ge 'of the dollyautomatically turn, in response to turning 'or tire towing vehicle, but"such, turning 'of the dolly is accomplished with sucientgradualnes'sthat the dolly wheels continue vto `roll rather than 'Skinning or beingdragged around a c orner whenthe lead ear makes a sharp turn. s,uichjresult is accomplished by useA of a pair 'of self-adjusting,reciprccally extensible and Ir,eti@afstaan steering arms, connectingopposite sides of the 'undrcarnage with the towing vehicle, the armolosest to the turning 'point being autmatiicllv compressed while theOpposite 'arm S "simultaneously 'extended in making 'al turn.

Other objects and advantages of the invention will be apparent from the'following description and claims, the novelty consfisting' in thefeatures of construction, Vc'omb'ination of parts, the unique relationsof the members andthe relative proportion-ing, disposition, 'andoperation thereof, all 'as more cbmpl'etely outlined herein andparticularly pointed out in the appended claims.

Referring to the drawings, which Vform part 'o f the presentspecification:

Figure 1 isa side elevational vleiw of my improved dolly with a trailerand towing' car `connected thereto;

Fig. 2 is a top plan View of the dolly with the trailer body removed;

Fig. 3 is a medial longitudinal sectional view of Figure l, taken alongthe line 3-3 of Figure 2,;

Fig. 4 is a transverse 'sectional View vthrough the axis of rotation ofthe dolly, taken 'along the line 4'-^4 ofl Figure 3;

Fig. 5 isa side View, partly in elevation and part in section, through atie rod; and

Fig. 6 is a top 'plan view showing Athe dolly in revolved or turningposition As here illustrated, the base ofthe `dolly con; sists'of a'generally rectangular frame lll coni@ posed of a pair of longitudinal'supports 'l2 and I4' rigidly joined to 'each `other near their res'pective ends by a pair of transverse members `I6. and I8. Suspended beneaththe opposite ends o f each longitudinal support is a downwardly bowedleale spring assembly, 20 and 2 2 respectively, at theA lowermost pointof each or which is attached a housing 24 and 26, which housings jointly'serve to journal a transverse 'axle 2'8 carrying a wheel' 55 3U oneither fend thereof.

Above the frame l0 there is located a hori; zontally rotatable orv lifthlwheel structure consisting of 'a 'pair of swivel plates, verticallyspaced apart 'and fixed in relation to each other, here "fO'rm'e'iCl ofannular (3,2) and polygonal v('34) shape, respectively. A centrallylocated, upstandin'g p'intle 36 is journalle'd jointly by the twoplates, being connected at its lower extremity to a `loiorizontalspindle 38 which 'in turn has its opposite ends journalled in thetransverse sup-4 ports, IB and' "IB of the frame. A longitudinal,medians'. positioned tongue 'MlA extends forward irom the uppervnolvgo'nel plate 34,' its 'upper face disposed' substantially flushtherewith.

A'p'air of forwardly converging, inwardly iacin'g, L-shaped brackets 42and 44 are carried by the upper swivel plate and 'adapted' to Supportjointly therebetween a correspondingly shaped pair of extension arms 46and 48 oi a trailer 50 the extension arms converging in a conventional ball and socket type vcoupling 5 2 which is here fastened to the frontend of the tongue 40. When the dolly is notavailable, the coupling 52can of course be attached directly to a towing vehicle.

= The trailer arms :46 vand 4'8 may be additionally secured to theL-brackets 42 and 44 by a cross piece 49 laid vtransvers ely on top ofboth trailer arms and bolted 'along the inner side of each to the bottomof each 'bracket at 5| and 53 4respectively.

By the present dolly construction, the trailer, secured to 'the -swivelplates 32 and 34, may revolve horizontally about the pintle ySii whilethe wheels 30 may rock vertically beneath the trailer on the spindle 38.Thus, when one wheel or the I other strikes a bump 'or depression in theroad,

the frame Hl can tilt beneath the swivel structure and its supportedtrailer without rocking or jarringv the latter. l

vIt also acts as a 'weight equalizer so that each wheel gets an equalshare of the weight when the road is uneven.

A pair of vertically swingable lead arms 54 'and 5.6 are attached toopposite sides of the swivel structure, said arms converging' to *allat, tri'- a'ngularbracket 58, the nose of which is provided with aballfand-s'ocket coupling 60 Afor* attachment to a lead vehicle 62. Thebracket 5B is centrally traversed by a vertical shaft 54, the lowerextremity of which is fixed to the forward y end of the tongue 4D by anangle iron 66. Above the upper face lof the bracket 58, a coil spring B8is located on the shaft 6 4 andheld in compression by a core washer 6 9which `abuts against atensio'n nut 10 threadedly mounted on the shaft.'

This arrangement serves to cushion the vertical play of the lead arms 54and 56 of the dolly.

It also is a means of putting part of the forward trailer weight on thedraw bar of the towing vehicle.

To put more weight on the draw bar of the towing vehicle the tension nut1U is tightened down. When the tension nut is loosened the dolly carriesthe weight.

At the point of attachment of the ball-andsocket connection 60 of thedolly to the lead vehicle 62, there is rigidly secured to the latter atransverse bar 12, the opposite ends of which are linked to thecorresponding sides of the dolly frame I6 by a pair of extensible andcompressible tie rods or steering arms 14 and 16. Each tie rod (Figure5) consists of a hollow cylinder 16, the forward end of which is formedby a tapped plug 86 adapted to threadedly receive the rod 82 Aand 84from the steering bar 12. The rear section of each cylinder 18 isoccupied by a coil spring 86, which seats against the back wall 88 ofthe chamber, the front end of the helix B6 being connected to an axiallyslidable draw rod 89 or 90 which in turn is secured to the longitudinalsupports I2 or I4 of the frame as the case may be.

The lead arms 54 and 56 can move vertically to allow for dips and highplaces in the road, but they cannot swing sideways which has a number ofadvantages. This is a safety factor on slick roads. Also, it is notpossible for the towing vehicles rear wheels to skid unless the dollywheels skid also in the same direction. If the lead arms 54 and 56 couldswing sideways, the dolly could skid one direction and cause the towingvehicle to skid in the opposite direction and the trailer would push toone side and forward up against a rear corner of the towing vehiclewhich might cause damage to the trailer and towing vehicle, or evencause a wreck if occuring while traveling at high speed.

Also, by the lead arms 54 and 56 not being permitted to swing sidewaysand by the dolly being guided by the steering arms 14 and 16, thetrailer is backed like any two wheeled trailer. The dolly is simplyguided beneath the front of the trailer by the steering arms and cannotswing around sideways, thus making the backing operation a simple matterfor the driver.

It is important to note in this connection that the length of thesteering bar 12, or rather the horizontal distance between the points ofconnection of the two tie rods 14 and 16 or their cables 82 and 84connected thereto, is less than the distance between the oppositeconnections of these tie rods to the dolly frame at 92 and 94respectively. By this arrangement, as seen in Figure 6, the degree ofturning of the dolly frame will be in graduated proportion to, ratherthan simultaneously equal to, the turning of the lead vehicle. In thismanner, a sudden swerve of the lead vehicle will not jerk the dollyundercarriage sidewise beyond the ability of the wheels to roll, but incontrast the compression of one steering arm (such as 14 in Fig. 6) andextension of the other (such as 16 in Fig. 6) due to the action of theirrespective helices will effect a gradual arcing path of the wheels 30.It will be observed also that the tie rods are of suiicient height forthe adjacent wheels to move beneath them.

While I have shown and described in some detail a presently preferredembodiment of my self-guiding trailer dolly, it is to be understood thatvarious modifications may be made in the construction and operationthereof within th scope of the subsequently claimed invention which isto be construed broadly and limited only by the prior art.

I claim:

1. A dolly for a trailer and the like, including: a frame having a wheeloperatively mounted on each side thereof, a horizontally rotatablestructure adapted to support a trailer body disposed above said frame,coupling means adapted to secure a trailer to said dolly, verticallyswingable coupling means adapted to secure said dolly to a towingvehicle, said coupling means being centrally attached to a steering barhorizontally disposed at the rear of said vehicle, and a pair ofgenerally horizontally disposed, reciprocally eX- pansible andcontractable tie rods, fixedly secured to opposite sides of said frameand pivotally attached adjacent the opposite ends of said steering barrespectively, the lateral displacementof said tie rods at their pointsof attachment to the towing vehicle being less than at their attachmentto said frame, each of said tie rods comprising a tubular member, acable extending from either end to the dolly and towing vehiclerespectively, and a coil spring disposed within said tube and attachedto one of said cables so as to allow it to reciprocate longitudinallywithin the tube with the expansion and contraction of the coil spring.

2. A d olly for a trailer and the like, including: a frame having awheel operatively mounted on each side thereof, a horizontally rotatablestructure adapted to support a trailer body disposed above said frame,bracket means on said structure adapted to detachably retain a pair oftrailer arms thereon,v a pair of lead arms vertically swingable on saidstructure and adapted to be coupled to a towing vehicle, said couplingmeans being centrally attached to a steering bar horizontally disposedat the rear of said vehicle and a pair of generally horizontallydisposed, reciprocally eXpansible and contractable tie rods, xedlysecured to opposite sides of said frame and pivotally attached adjacentthe opposite ends of said steering bar respectively, the lateraldisplacement of said tie rods at their Vpoints of attachment to thetowing vehicle being less than at their attachment to said frame, eachof said tie rods comprising a tubular member, a cable extending fromeither end to the dolly and towing vehicle respectively, and a coilspring disposed within said tube and attached to one of said cables soas to allow it to reciprocate longitudinally within the tube with theexpansion andv contraction of the coil spring.

3. A dolly for a trailer and the'like, including: a frame having a wheeloperatively mounted on each side thereof, a horizontally rotatablestructure adapted to support a trailer body disposed above said frame,coupling means adapted to secure a trailer to said dolly, verticallyswingable coupling means adapted to secure said dolly to a towingvehicle, said coupling means being centrally attached to a steering barhorizontally disposed. at the rear of said vehicle and a pair ofgenerally horizontally disposed, reciprocally expansible andcontractable tie rods, xedly secured to opposite Vsides of said frameand pivotally atspectively, and a coil spring disposed within said tubeand attached to one of said cables so as t0 aires-,rre

allow it to reciprocate longitudlnally'within the tube with theexpansion and contractionof the coil spring.

4. A dolly for a trailer and the like, including: a frame having a Wheeloperatively mounted on each side thereof, a horizontally rotatablestructure adapted to support a trailer body disposed above said frame,bracket means on .said structure adapted to detachably retain a pair oftrailer arms thereon, a pair of lead arms vertically swingable on saidstructure and adapted to be coupled'to a towing vehicle, said couplingmeans being centrally attached to a steering bar horizontally disposedat the rear of said vehicle and a pair ofv generally horizontallydisposed, reciprocally expansible and contractable tie rods, xedlysecured to opposite sides of said frame and pivotally attached adjacentthe opposite ends of said steering bar respectively, each of said tierods comprising a tubular member, a cable extending from either end tothe dolly and towing vehicle respectively, and a coil spring disposedwithin said tube and attached to one of said cables so as to allow it toreciprocate longitudinally Within the tube with the expansion andcontraction of the coil spring.

5. A dolly `for a trailer and the like, including: a frame having awheel operatively mounted on each side thereof, a horizontally rotatablestructure adapted to support a trailer body disposed above said frame,coupling means adapted to secure a trailer to said dolly, verticallyswingable coupling means adapted to secure said dolly to a towingvehicle, and a pair of generally horizontally disposed, reciprocallyexpansible and contractable tie rods, iixedly secured to opposite sidesof said frame and pivotally attached adjacent the opposite sides of saidtowing vehicle, each of said tie rods comprising a tubular member, acable extending from either end to the dolly and towing vehiclerespectively, and a coil spring disposed within said tube and attachedto one of said cables so as to allow it to reciprocate longitudinallywithin the tube with the expansion and contraction of the coil spring.

6. A dolly for a trailer and the like, including: a frame having a wheeloperatively mounted on each side thereof, a horizontally rotatablestructure adapted to support a trailer body disposed above said frame,coupling means adapted to secure a trailer to said dolly, verticallyswingabl'e coupling means adapted to secure said dolly to a towingvehicle, and a pair of generally horizontally disposed, reciprocallyexpansible and contractable tie rods, fixedly secured to opposite sidesof said frame and pivotally attached adjacent the opposite sides of saidtowing vehicle, the lateral displacement of said tie rods at theirpoints of attachment to the towing vehicle being less than at theirattachment to said frame; each of said tie rods comprising a tubularmember, a cable extending from either end to the dolly and towingvehicle respectively, and a coil spring disposed within said tube andattached to one of said cables so as to allow it to reciprocatelongitudinally within the tube with the expansion and contraction of thecoil spring.

7. A dolly for a trailer and the like, including: a frame having a wheeloperatively mounted on each side thereof, a horizontally rotatablestructure adapted to support a trailer body disposed above said frame,bracket means on said structure adapted to detachably retain a pair oitrailer arms thereon, a pair of lead arms vertically swingable on saidstructure and adapted to be coupled to a :towing venian, and a pair of'generally horizontally disposed, reciprocally expansible andcontractable tie rods, xedly secured to opposite sides of said frame andpivotally attachedadjacent the opposite sides of said towing vehicle,each of said tie rods comprising a tubular member, a cable extendingfrom either end to the dolly and towing vehicle respectively,

and a coil spring disposed within said tube and y attached to one ofsaid cables so as to allow it to reciprocate longitudinally within thetube with the expansion and contraction of the coil spring.

8. A dolly for a trailer and the like, including: a frame having a wheeloperatively mounted on each side thereof, a horizontally rotatablestructure adapted to support a trailer body disposed above said frame,bracket means on said structure adapted to detachably retain a pair oftrailer arms thereon, a pair of lead arms vertically swingable on saidvstructure and adapted to be coupled to a towing vehicle,'and a pair ofgenerally horizontally disposed, reciprocally expansible andcontractable tie rods, iixedly secured to opposite sides of said frameand pivotally attached adjacent the opposite sides of said towingvehicle, the lateral displacement of said tie rods at their points 'ofattachment to the towing vehicle being less than at their attachment tosaidframe, yeach of said tie rods comprising a tubular member, a cableextending from either end to the dolly and towing vehicle respectilely,and a coil spring disposed Within said tube and attached to one of saidcables so as to allow it to reciprocate longitudinally within the tubewith the expansion and contraction of the coil spring.

9. A dolly for a trailer and the like including: a frame having a wheeloperatively mounted on each side thereof, a horizontally rotatablestructure adapted to support a trailer body disposed above said frame,coupling means adapted to secure a trailer to said dolly, verticallyswingable coupling means adapted to secure said dolly to a towingVehicle, a horizontally rigid vertically movable tongue, and a pair ofgenerally horizontally disposed, reciprocally expansible andcontractable tie rods, lxedly secured to opposite sides of said frameand pivotally attached adjacent the opposite ends of said steering barrespectively, each of said tie rods comprising a tubular member, a cableextending from either end to the dolly and towing Vehicle respectively,and a coil spring disposed within said tube and attached to one of saidcables so as to allow it to reciprocate longitudinally within the tubewith the expansion and contraction of the coil spring.

10. A dolly for a trailer and the like including: a frame having a wheeloperatively mounted on each side thereof, a horizontally rotatablestructure adapted to support a trailer body disposed above said frame,coupling means adapted to secure a trailer to said dolly, verticallyswingable coupling means adapted to secure said dolly to a towingvehicle, a horizontally rigid vertically movable tongue said couplingmeans being fastened to the front end of said tongue, the rearward endof said tongue being hingedly mounted on said dolly, a pair of generallyhorizontally disposed, reciprocally expansible and contractable tierods, xedly secured to opposite sides of said frame and pivotallyattached adjacent the opposite ends of said steering bar respectively,the lateral displacement of said tie rods at their points of attachmentto the towing vehicle being less than at their attachment to said frameand a fifth wheel to effect rotation at a point midway between theWheels.

11. A dolly for a trailer and the like including: a frame having a wheeloperatively mounted on each side thereof, a horizontally rotatablestructure adapted. to support a trailer body disposed above said frame,coupling means adapted to secure a trailer to said dolly, verticallyswingable coupling means adapted to secure said dolly to a towingvehicle, means for transferring the weight of said trailer from saiddolly to said towing vehicle, and a pair of generally horizontallydisposed, reciprocally expansible and contractable tie rods, flxedlysecured to opposite sides of said frame and pivotally attached adjacentthe opposite ends of said steering bar, respectively, each of said tierods comprising a tubular member, a cable extending from either end tothe dolly and towing vehicle respectively, anda coil spring disposedwithin said tube and attached to one of said cables so as to allow it toreciprocate longitudinally within the tube with the expansion andcontraction of the coil spring.

12. A dolly for a trailer and the like including: a frame having a wheeloperatively mounted on each side thereof, a horizontally rotatablestructure adapted to support a trailer body disposed above said frame,coupling means adapted to secure a trailer to -said dolly, verticallyswingable coupling means adapted to secure said dolly to a towingvehicle, manually adjustable means for transferring the weight of saidtrailer from said towing vehicle to said dolly, a pair of generallyhorizontally disposed, reciprocally expansible and contractable tierods, xedly secured to opposite sides of said frame and pivotallyattached adjacent the opposite ends of said steering bar respectively,the lateral displacement of said tie rods at their points of attachmentto the towing vehicle being less than at their attachment to said frameand a fifth Wheel to effect rotation at a point midway between thewheels.

FRANKLIN L. WINCHESTER.

REFERENCES CITED The following references are of record in the le ofthis patent:

UNITED STATES PATENTS Number Name Date 990,793 Woodward Apr. 25, 19112,001,408 Burton May 14, 1935 2,180,257 Rollins NOV. 14, 1939 2,206,991Williams et al. July 9, 1940 2,410,241 Schramm Oct. 29, 1946

